Community access television, or cable television, (CATV) networks use an infrastructure of interconnected coaxial cables, splitters, amplifiers, filters, trunk lines, cable taps, drop lines and other signal-conducting devices to supply and distribute high frequency “downstream” signals from a main signal distribution facility, known as a head-end, toward subscriber premises such as homes and businesses. The downstream signals operate the subscriber equipment, such as television sets, telephones, and computers. The typical CATV network is a two-way communication system. CATV networks also transmit “upstream” signals from the subscriber equipment back to the head-end of the CATV network. For example, upstream bandwidth may include data related to video-on-demand services, such as video requests and billing authorization. Two-way communication is also utilized when using a personal computer connected through the CATV infrastructure to the public Internet, for example when sharing photo albums or entering user account information. In yet another example, voice over Internet protocol (VOIP) telephones and security monitoring equipment use the CATV infrastructure and the public Internet as the communication medium for transmitting two-way telephone conversations and monitoring functions.
To permit simultaneous communication of upstream and downstream CATV signals and the interoperability of the subscriber equipment and the equipment associated with the CATV network infrastructure outside of subscriber premises, the downstream and upstream CATV signals are confined to two different frequency bands. In most CATV networks the downstream frequency band, or downstream bandwidth, is within the range of 54-1002 megahertz (MHz) and the upstream frequency band, or upstream bandwidth, is within the range of 5-42 MHz.
The downstream signals are delivered from the CATV network infrastructure to the subscriber premises at a CATV entry adapter, which is also commonly referred to as an entry device, terminal adapter or a drop amplifier. The entry adapter is a multi-port device which connects at a premises entry port to a CATV drop cable from the CATV network infrastructure. The entry adapter connects at a multiplicity of other distribution ports to coaxial cables which extend throughout the subscriber premises to a cable outlet. Each cable outlet is available to be connected to subscriber equipment. Typically, most homes have coaxial cables extending to cable outlets in almost every room, because different types of subscriber equipment may be used in different rooms. For example, television sets, computers and telephone sets are commonly used in many different rooms of a home or office. The multiple distribution ports of the entry adapter deliver the downstream signals to each cable outlet and conduct the upstream signals from the subscriber equipment through the entry adapter to the drop cable and the CATV infrastructure.
In addition to television sets, computers and telephones, a relatively large number of other entertainment and multimedia devices are available for use in homes. For example, a digital video recorder (DVR) is used to record broadcast programming, still photography and moving pictures in a memory medium so that the content can be replayed on a display or television set at a later time selected by the user. As another example, computer games are also played at displays or on television sets. Such computer games may be those obtained over the Internet from the CATV network or from media played on play-back devices connected to displays or television sets. In another example, receivers of satellite-broadcast signals may be distributed for viewing or listening throughout the home. These types of devices, including the more-conventional television sets, telephone sets and devices connected to the Internet by the CATV network, are generically referred to as multimedia devices.
An in-home entertainment network may be coupled to the CATV network via the same coaxial cable delivering the downstream and upstream bandwidth of the CATV system. The in-home entertainment network can be a network providing multiple streams of high definition video and gaming entertainment. Examples of in-home entertainment network technologies include Ethernet, HomePlug, Home Phoneline Networking Alliance (HPNA), Multimedia over Coax Alliance (MoCA) and 802.11n protocols. The in-home entertainment (IHE) network is coupled to the CATV network within a subscriber premises to allow the CATV network to distribute IHE signals from one multimedia device to another within the subscriber premises.
Since the operation of the subscriber premises IHE network must occur simultaneously with the operation of the CATV services, the IHE signals often utilize a frequency range different from the frequency ranges of the CATV upstream and downstream signals. A typical IHE frequency band is 1125-1675 MHz, which is referred to in this document as the multimedia-over-coax frequency range, or bandwidth. A specific IHE network technology can includes other frequency ranges, but the 1125 to 1675 MHz frequency range is of major relevance because of its principal use in establishing connections between the multimedia devices within a subscriber network.
Although using the in-home cable infrastructure as the communication medium substantially simplifies the implementation of the IHE network, there are certain disadvantages to doing so. One noted problem arises when multimedia-over-coax signals pass backwards through a conventional splitter en route to another multimedia-over-coax-enabled device within the network. The CATV network and the in-home cable infrastructure were originally intended for the distribution of CATV signals. The typical in-home cable infrastructure uses signal splitters to divide CATV downstream signals into multiple CATV downstream paths and to combine multiple CATV upstream signals into a single CATV upstream path. The CATV entry adapter was not originally intended to communicate multimedia-over-coax signals between its ports, as is necessary to achieve multimedia-over-coax signal communication in the IHE network. To implement the IHE network, the multimedia-over-coax signals must traverse between separate signal component legs of a signal splitter/combiner which are connected to the multiple ports.
The typical signal splitter has a high degree of signal rejection or isolation between its separate signal component legs. When the multimedia-over-coax signals traverse between the separate signal component legs of the splitter, the degree of signal rejection or isolation greatly attenuates the strength of the multimedia-over-coax signals. This it is desirable to have a system which transmits both CATV and IHE signals without attenuating or rejecting the IHE signals to a large degree.
Some IHE network communication protocols recognizes the possibility of variable strength multimedia-over-coax signals and provide the capability to boost the strength of multimedia-over-coax signals to compensate for the variable strength of the multimedia-over-coax signals that are communicated between multimedia-over-coax-enabled devices. However, boosting the strength of the multimedia-over-coax signal can result in the strength or power of the multimedia-over-coax signals being substantially greater than the strength or power of the CATV signals communicated within the subscriber premises. Consequently, the multimedia-over-coax signals have the capability of adversely affecting the proper functionality of standard CATV subscriber equipment, such as a digital video recorder or an embedded multimedia terminal adapter (eMTA). This it is desirable to have a device for use in a CATV network which conditions the IHE signals transmitted through the network such that the IHE signals will not be rejected, without adversely affecting the CATV communication occurring simultaneously on the CATV network.